Proline: Mother Nature;s cryoprotectant applied to protein crystallography

Journal Article · Wed Sep 05 00:00:00 EDT 2012 · Acta Crystallogr. D

DOI:https://doi.org/10.1107/S0907444912019580· OSTI ID:1047307

Pemberton, Travis A; Still, Brady R; Christensen, Emily M; Singh, Harkewal; Srivastava, Dhiraj; Tanner, John J ^[1]

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1. UMC

L-Proline is one of Mother Nature's cryoprotectants. Plants and yeast accumulate proline under freeze-induced stress and the use of proline in the cryopreservation of biological samples is well established. Here, it is shown that L-proline is also a useful cryoprotectant for protein crystallography. Proline was used to prepare crystals of lysozyme, xylose isomerase, histidine acid phosphatase and 1-pyrroline-5-carboxylate dehydrogenase for low-temperature data collection. The crystallization solutions in these test cases included the commonly used precipitants ammonium sulfate, sodium chloride and polyethylene glycol and spanned the pH range 4.6-8.5. Thus, proline is compatible with typical protein-crystallization formulations. The proline concentration needed for cryoprotection of these crystals is in the range 2.0-3.0 M. Complete data sets were collected from the proline-protected crystals. Proline performed as well as traditional cryoprotectants based on the diffraction resolution and data-quality statistics. The structures were refined to assess the binding of proline to these proteins. As observed with traditional cryoprotectants such as glycerol and ethylene glycol, the electron-density maps clearly showed the presence of proline molecules bound to the protein. In two cases, histidine acid phosphatase and 1-pyrroline-5-carboxylate dehydrogenase, proline binds in the active site. It is concluded that L-proline is an effective cryoprotectant for protein crystallography.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: National Institutes of Health (NIH)
• OSTI ID: 1047307
• Journal Information: Acta Crystallogr. D, Vol. 68, Issue (8) ; 08, 2012
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
ACID PHOSPHATASE
AMMONIUM SULFATES
CRYSTALLIZATION
CRYSTALLOGRAPHY
CRYSTALS
DATA
DIFFRACTION
ELECTRON DENSITY
GLYCEROL
GLYCOLS
HISTIDINE
LYSOZYME
MOLECULES
OXIDOREDUCTASES
PLANTS
POLYETHYLENE GLYCOLS
PROLINE
PROTEINS
RANGE
RESOLUTION
SODIUM CHLORIDES
SOLUTIONS
STATISTICS
TEMPERATURE RANGE 0065-0273 K
XYLOSE
YEASTS